#include <iostream>

using namespace std;

void swap(int v1,int v2)
{
	int tmp = v2;
	v2 = v1;
	v1 = tmp;
}

int main()
{
	int i = 10;
	int j = 20;
	cout<<"Before swap i: "<<i<<" ,j: "<<j<<endl;
	swap(i,j);
	cout<<"After swap i: "<<i<<" ,j: "<<j<<endl;
	return 0;
}